To adequately evaluate treatment status of type 1 diabetes in adolescents, valid and reliable measures of both biological status and self-management are necessary. Currently, no self-report measure of self-management exists. The proposed study will develop and test the SMOD-A, a comprehensive measure of adolescent self-management of type 1 diabetes. The aims of the study are: 1) To complete the development of the Self-Management of Diabetes in Adolescents (SMOD-A); 2) To evaluate the content validity and clarity of the SMOD-A items through input from expert pediatric diabetes clinicians and researchers (panel 1), adolescents who have been identified as good self-managers of type 1 diabetes (panel 2), and parents of good self-managers of the disease (panel 3); 3) To pilot test the instrument with adolescents with type 1 diabetes in order to evaluate SMOD-A instructions, items, and response format (stage one) and to evaluate data collection procedures and supply pilot data (stage two); and 4) To determine the psychometric properties of the SMOD-A through a field test. Aim 1 has already been accomplished. The SMOD-A will be evaluated for content validity by three expert panels (Aim 2). To meet Aim 3, adolescents from the Yale site will be asked to evaluate the SMOD-A instructions, items and item response format (n = 20; stage one); and to evaluate data collection procedures and supply pilot data (n = 20; stage two). To meet Aim 4, 600 adolescents will be enrolled (Yale and CHOP). Participants will complete the SOMD-A, a measure of self-management or adherence (DSMP or SCI), a measure of diabetes self-efficacy, a measure of diabetes quality of life, and the CABS. The factor structure of the SMOD-A will be assessed using exploratory and confirmatory factor analyses. To assess test-retest reliability, participants will be complete a second SMOD-A at 2 weeks (n = 30 at each site) and 3 months (n = 30 at each site)). Convergent and discriminant construct validity will be assessed my measuring the predicted relationships of the SMOD-A scores and scores on three measures related to diabetes management in adolescents, between SMOD-A scores and scores on an interview measure of self-management and a self-report measure of adherence, between SMOD-A scores and age and duration of illness, and between SMOD-A Scores and scores on an unrelated measure. [unreadable] [unreadable]